Ezrin is a downstream effector of trafficking PKC-integrin complexes involved in the control of cell motility

EMBO J. 2001 Jun 1;20(11):2723-41. doi: 10.1093/emboj/20.11.2723.


Protein kinase C (PKC) alpha has been implicated in beta1 integrin-mediated cell migration. Stable expression of PKCalpha is shown here to enhance wound closure. This PKC-driven migratory response directly correlates with increased C-terminal threonine phosphorylation of ezrin/moesin/radixin (ERM) at the wound edge. Both the wound migratory response and ERM phosphorylation are dependent upon the catalytic function of PKC and are susceptible to inhibition by phosphatidylinositol 3-kinase blockade. Upon phorbol 12,13-dibutyrate stimulation, green fluorescent protein-PKCalpha and beta1 integrins co-sediment with ERM proteins in low-density sucrose gradient fractions that are enriched in transferrin receptors. Using fluorescence lifetime imaging microscopy, PKCalpha is shown to form a molecular complex with ezrin, and the PKC-co-precipitated endogenous ERM is hyperphosphorylated at the C-terminal threonine residue, i.e. activated. Electron microscopy showed an enrichment of both proteins in plasma membrane protrusions. Finally, overexpression of the C-terminal threonine phosphorylation site mutant of ezrin has a dominant inhibitory effect on PKCalpha-induced cell migration. We provide the first evidence that PKCalpha or a PKCalpha-associated serine/threonine kinase can phosphorylate the ERM C-terminal threonine residue within a kinase-ezrin molecular complex in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Breast Neoplasms
  • Cell Membrane / metabolism
  • Cell Membrane / ultrastructure
  • Cell Movement / drug effects
  • Cell Movement / physiology*
  • Chromones / pharmacology
  • Cytoskeletal Proteins
  • Enzyme Inhibitors / pharmacology
  • Female
  • Green Fluorescent Proteins
  • Humans
  • Integrin beta1 / physiology*
  • Isoenzymes / metabolism*
  • Kinetics
  • Luminescent Proteins / analysis
  • Luminescent Proteins / genetics
  • Microscopy, Confocal
  • Morpholines / pharmacology
  • Mutagenesis, Site-Directed
  • Phorbol 12,13-Dibutyrate / pharmacology
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphoproteins / chemistry*
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Phosphothreonine / metabolism
  • Protein Kinase C / metabolism*
  • Protein Kinase C-alpha
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / chemistry
  • Tumor Cells, Cultured
  • Wound Healing / physiology*


  • Chromones
  • Cytoskeletal Proteins
  • Enzyme Inhibitors
  • Integrin beta1
  • Isoenzymes
  • Luminescent Proteins
  • Morpholines
  • Phosphoproteins
  • Recombinant Fusion Proteins
  • ezrin
  • Phosphothreonine
  • Green Fluorescent Proteins
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • Phorbol 12,13-Dibutyrate
  • Phosphatidylinositol 3-Kinases
  • PRKCA protein, human
  • Protein Kinase C
  • Protein Kinase C-alpha